Messages in this thread | | | Date | Thu, 05 Jul 2012 15:42:34 +0400 | From | Sergei Shtylyov <> | Subject | Re: [PATCH v2 2/2] ata: implement MODE SELECT command |
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Hello.
On 05-07-2012 13:40, Paolo Bonzini wrote:
> The cache_type file in sysfs lets users configure the disk cache in > write-through or write-back modes. However, ata disks do not support > writing to the file because they do not implement the MODE SELECT > command.
> This patch adds a translation from MODE SELECT (for the caching page > only) to the ATA SET FEATURES command. The set of changeable parameters > answered by MODE SENSE is also adjusted accordingly.
> Cc: Sergei Shtylyov <sshtylyov@mvista.com> > Cc: Jeff Garzik <jgarzik@pobox.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > drivers/ata/libata-scsi.c | 185 +++++++++++++++++++++++++++++++++++++++++++-- > 1 files changed, 179 insertions(+), 6 deletions(-)
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c > index d5aeb26..1cb88df 100644 > --- a/drivers/ata/libata-scsi.c > +++ b/drivers/ata/libata-scsi.c [...] > +/** > + * ata_scsiop_mode_select - Simulate MODE SELECT 6, 10 commands > + * @qc: Storage for translated ATA taskfile > + * > + * Converts a MODE SELECT command to an ATA SET FEATURES taskfile. > + * Assume this is invoked for direct access devices (e.g. disks) only. > + * There should be no block descriptor for other device types. > + * > + * LOCKING: > + * spin_lock_irqsave(host lock) > + */ > +static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc) > +{ > + struct scsi_cmnd *scmd = qc->scsicmd; > + const u8 *cdb = scmd->cmnd; > + const u8 *p; > + u8 pg, spg; > + unsigned six_byte, pg_len, hdr_len; > + int len; > + > + VPRINTK("ENTER\n"); > + > + six_byte = (cdb[0] == MODE_SELECT); > + if (six_byte) { > + if (scmd->cmd_len < 5) > + goto invalid_fld;
Strictly speaking, it should be "invalid phase" error.
> + > + len = cdb[4]; > + } else { > + if (scmd->cmd_len < 9) > + goto invalid_fld;
The same.
> + > + len = (cdb[7] << 8) + cdb[8]; > + } > + /* Test early for possible overrun. */ > + if (!scsi_sg_count(scmd) || scsi_sglist(scmd)->length < len) > + goto invalid_param_len;
Strictly speaking, it's "data underrun" error.
> + p = page_address(sg_page(scsi_sglist(scmd)));
What if the S/G list spans multiple non-consecutive pages?
> + > + /* Move past header and block descriptors. */ > + if (six_byte) > + hdr_len = p[3] + 4; > + else > + hdr_len = (p[6] << 8) + p[7] + 8; > + > + if (len < hdr_len) > + goto invalid_param_len; > + > + len -= hdr_len; > + p += hdr_len; > + if (len == 0) > + goto skip; > + > + /* Parse both possible formats for the mode page headers. */ > + pg = p[0] & 0x3f; > + if (p[0] & 0x40) { > + if (len < 4) > + goto invalid_param_len; > + > + spg = p[1]; > + pg_len = (p[2] << 8) | p[3]; > + p += 4; > + len -= 4; > + } else { > + if (len < 2) > + goto invalid_param_len; > + > + spg = 0; > + pg_len = p[1]; > + p += 2; > + len -= 2; > + } > + > + /* > + * Only one page has changeable data, so we only support setting one > + * page at a time. > + */ > + if (len < pg_len) > + goto invalid_param;
Not 'invalid_param_len'?
> + > + /* > + * No mode subpages supported (yet) but asking for _all_ > + * subpages may be valid > + */ > + if (spg && (spg != ALL_SUB_MPAGES)) > + goto invalid_param;
Rather "paramater not supported" (0x26/0x01)...
> + if (pg_len > len) > + goto invalid_param_len;
We have just checked this.
> + switch (pg) { > + case CACHE_MPAGE: > + if (ata_mselect_caching(qc, p, pg_len) < 0) > + goto invalid_param;
Rather "parameter not supported"?
> + break; > + > + default: /* invalid page code */ > + goto invalid_param;
Rather "paramater not supported"...
> + } > + > + return 0;
MBR, Sergei
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